Armature assembly apparatus

ABSTRACT

An armature assembly apparatus for assembling an armature of an electrical machine is provided. The armature assembly apparatus has an armature holding apparatus to hold a partially assembled armature such that a rotation axis of the armature is horizontal. The armature assembly apparatus has a rotating device for rotating the partially assembled armature about a rotation axis. The armature assembly apparatus also has a ring segment conveyance for conveying an armature ring segment to a mounting position relative to a free ring segment portion of the partially assembled armature.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of European Patent Office applicationNo. 12150741.2 EP filed Jan. 11, 2012, which is incorporated byreference herein in its entirety.

FIELD OF INVENTION

The application describes an armature assembly apparatus for assemblingan armature of an electrical machine; an armature holding apparatus; aring segment conveyance; and a method of assembling an armature of anelectrical machine.

BACKGROUND OF INVENTION

A conventional wind turbine generally comprises a gearbox to increasethe rotational speed of its generator relative to its rotor shaft and toincrease the pole change frequency. A gearbox comprises many componentsthat are subject to wear and must be maintained or replaced atintervals. Complex and expensive bearing arrangements are also requiredto bear the extreme loads and torque acting on the rotor shaft and thegearbox. A direct-drive wind turbine has several features over such aconventional wind turbine, whereby a major feature is that adirect-drive turbine does not require such a gearbox. A direct-drivewind turbine requires fewer parts, is less complex, and more reliable.For these reasons, demand for direct drive wind turbines is increasing.

A direct-drive generator has a relatively large diameter and manymagnets of altering polarity arranged along a circumference of a fieldmagnet arrangement—usually an outside rotor—to allow for a sufficientlyhigh pole-change frequency. The physical dimensions and weight of such alarge generator pose problems during its assembly. Handling of theheavy, unwieldy and vulnerable components is complex and time-consuming,and is also hazardous, so that strict safety measures must be adheredto. This adds considerably to the overall time and cost required for theassembly of a direct-drive generator.

For example, stator ring segments must be handled with care, but eachring segment can weigh hundreds of kilos, making it difficult tomanoeuvre into position ready for mounting to a stator bedframe, whichusually comprises a frontplate and a backplate mounted to a hollowstator shaft. A stator ring segment generally comprises several coilsections with windings wrapped in isolating material, and end-sectionsshaped to be connected to end-sections of neighbouring ring segments.Usually, a stator ring segment is transported to the partially assembledstator using a hoisting or crane, and is connected to this by cables orchains. The ring segment must be suspended in place until it is mountedto the stator bedframe. Extreme care must be taken when the ring segmentis suspended during transport so that the vulnerable parts such asinsulation or connectors are not damaged or bent, and so that theisolating material is not damaged. Furthermore, care must be taken toavoid damage or distortion of bedframe connecting device that arenecessary for connecting the ring segment to the stator bedframe,otherwise an exact mounting is not possible. Damage to any of theseelements results in expensive repair work and holds up production.

SUMMARY OF INVENTION

It is an object of the application to provide a more economical andreliable way of assembling an armature for a generator of a direct-drivewind turbine.

This object is achieved by the armature assembly apparatus of claim 1;by the armature holding apparatus of claim 8; by the ring segmentconveyance of claim 10; and by the method of claim 15 of assembling anarmature of an electrical machine.

According to the application, the armature assembly apparatus forassembling an armature of an electrical machine comprises an armatureholding apparatus realised to hold a partially assembled armature suchthat a rotation axis of the armature is horizontal; a rotating devicefor rotating the partially assembled armature about a rotation axis; anda ring segment conveyance for conveying an armature ring segment to amounting position relative to a free ring segment portion of thepartially assembled armature.

The armature holding apparatus or “assembly station” can be a framerealised to bear the weight of an assembled armature, and can also berealised to move from one point of an assembly line to another. Thearmature holding apparatus may also be referred to as an armature frameor armature transport frame in the following. In the armature assemblyapparatus according to the application, the rotation axis of thearmature is horizontal or parallel to the ground. This is in contrast toprior art assembly arrangements that involve a vertical orientation ofthe armature, as described in the introduction, and allows the armatureto be retained in that orientation for most or all of the assemblystages of the generator. In other words, various assembly stages can becarried out to the armature as it is held in the horizontal orientation,so that lifting equipment such as cranes and hoists are not required,and the armature or armature ring segments are held securely and cannotbe dropped and cannot swing against other components. A ring segmentdoes not have to be manually hoisted or lifted into place and held whileit is being secured to the armature, but can simply be brought into amounting position relative to the free ring segment portion using thering segment conveyance. A feature of the armature holding apparatusaccording to the application is that the sensitive and expensivecomponents are effectively protected from damage, and an elasticdeformation of the ring segment is avoided. Furthermore, the armatureholding apparatus according to the application effectively protects anarmature, primarily designed to bear the weight of the ring segments ina horizontal position, from any distortion.

According to the application, the armature holding apparatus, for use inthe assembly of an armature of an electrical machine, comprises aconnecting device for detachably connecting a partially assembledarmature to the armature holding apparatus such that a rotation axis ofthe armature is horizontal; and a rotating device for rotating thepartially assembled armature about a rotation axis.

According to the application, the ring segment conveyance for use in theassembly of an armature of an electrical machine comprises a support forsupporting an armature ring segment; and a positioning device forbringing the armature ring segment into a mounting position relative toa free ring segment portion of a partially assembled armature.

While such a ring segment conveyance could be realised to bring anarmature ring segment into position at an angle relative to thearmature, for example from the side or from above, the ring segmentconveyance according to the application is realised to bring a ringsegment into position from below the partially assembled armature. Inother words, the ring segment conveyance holds the armature ring segmentin position underneath the partially assembled armature. In this way,there is no risk of the ring segment slipping or being dropped before itcan be mounted to the armature.

According to the application, the method of assembling an armature of anelectrical machine comprises the steps of

-   (A) connecting a partially assembled armature to an armature holding    apparatus such that a rotation axis of the armature is horizontal;-   (B) actuating a rotating device to rotate the partially assembled    armature about a rotation axis of the rotating device to bring a    free ring segment portion into position;-   (C) conveying an armature ring segment to the partially assembled    armature;-   (D) controlling an adjusting device of the armature assembly    apparatus to bring the armature ring segment into a mounting    position on the free ring segment portion of the partially assembled    armature;-   (E) mounting the armature ring segment to the free ring segment    portion of the partially assembled armature;    and repeating steps to until a desired number of armature ring    segments have been mounted onto the armature. Of course, the    sequence or order in which these steps are carried out is not    limited to the order in which they are listed here.

The feature of the method according to the application is that it allowsthe armature to be assembled without the hazardous or time-consuminghandling steps known from the prior art. A number of armature ringsegments can be “lined up” ready for mounting, and as soon as one ringsegment is mounted to the partially assembled armature, this can berotated by a suitable amount so that the next ring segment can bemounted, and so on.

Embodiments and features of the application are given by the dependentclaims, as revealed in the following description. Features of differentclaim categories may be combined as appropriate to give furtherembodiments not described herein.

While the windings could be mounted on a rotating component of thegenerator, in a direct-drive wind turbine the windings are generallyarranged on a stationary stator, which is usually arranged inside therotor, i.e. the rotor comprises an outside rotor. In the following,without restricting the application in any way, it may be assumed thatthe armature is a stator, and the terms “armature” and “stator” may beused interchangeably in the following. Also, without restricting theapplication in any way, it may be assumed that the generator is for awind turbine. During assembly of the armature, it may be assumed thatthe ring segments are mounted to the exterior of the armature. It mayalso be assumed that an armature ring segment is a radial ring segment,i.e. the armature ring segment occupies a radial fraction of an exteriorcircumferential curved plane of the armature.

The expression “rotation axis of the armature” is to be understood asthe axis about which a rotating part of the assembled generator willrotate. Usually, the generator exhibits rotational symmetry about itsaxis of rotation. The rotating part can be the armature itself, in whichcase the field magnet arrangement of the generator can be stationary.Alternatively, the armature itself does not rotate, as would be the casefor a generator comprising a stationary armature and a rotating fieldmagnet arrangement.

The ring segment conveyance can be any suitable conveyance for bringinga ring segment to the partially assembled stator for mounting. Forexample, the ring segment conveyance can be realised as a type ofconveyor belt. However, an embodiment of the application, the ringsegment conveyance comprises a trolley or wagon arranged on wheels orrollers so that it is freely moveable relative to the stator frame. Inthe following, without restricting the application in any way, the ringsegment conveyance may be referred to simply as a “trolley” or “ringsegment trolley”.

The rotating device of the armature assembly apparatus can be realisedto rotate the partially assembled armature in any suitable manner. Forexample it may be realised to allow the partially assembled armature to“roll” along a predefined path, so that the rotational axis of thearmature is displaced in a horizontal direction parallel to the ground.However, in an embodiment of the application, the rotating device isrealised to rotate the partially assembled armature about the rotationaxis of the armature. In other words, the armature is not displacedlaterally and is only rotated about its own axis of rotation.

The partially assembled armature could simply be suspended in place suchthat it can engage with the rotating device during assembly of thearmature. However, an embodiment of the application, the armatureholding apparatus comprises a connecting device for detachablyconnecting the partially assembled armature to the rotating device, sothat the partially assembled armature is at all times securely fastenedto the transport frame.

The rotating device can comprise any suitable apparatus or device thatis realised to turn the relatively heavy armature. The rotating devicecomprises a meshed gear arrangement. For example such enmeshed in yourarrangement can comprise one large gear wheel realised to engage with asmaller driving you really substantially larger gear wheel is arrangedto accommodate a shaft of the stator. In an alternative arrangement, themeshed gear arrangement can comprise a set of helical gears, a worm andwheel arrangement, or a rack and pinion arrangement.

Such a rotating device is realised to be driven by a suitable actuatingdevice, for example a motor such as an electric motor. The actuatingdevice is realised to actuate the rotating device to rotate thepartially assembled armature about its rotation axis. In an embodimentof the application, the rotating device is realised to rotate thepartially assembled armature by a radial amount corresponding to aradial width of an armature ring segment. For example, if twelve ringsegments are to be mounted to the stator bedframe, the actuating devicecan be realised to rotate the partially assembled stator by 30°, so thatthe next free ring segment portion can be brought into position readyfor the next assembly step.

The armature assembly apparatus according to the application comprisessome kind of adjusting device for bringing the armature ring segmentinto a mounting position on the free ring segment portion of thepartially assembled armature. For example, the armature frame can berealised to be adjustable in the several degrees of freedom so that thepartially assembled armature itself is moved relative to a stationaryring segment held on the conveyance or trolley. However, the largedimensions and considerable weight of the partially assembled armaturecan make this relatively difficult to achieve. In an embodiment of theapplication, such an adjusting device is realised as part of thetrolley. In such a realisation, the armature frame can remain stationaryrelative to the trolley.

In a further embodiment of the application, the adjusting device oraligning device is realised to adjust the position of the armature ringsegment relative to the free ring segment portion of the partiallyassembled armature. To this end, the adjusting device can be connectedin some suitable way to a control interface or control module which canbe used by a controller, human or automated, to control the adjustingdevice. For example, such a control module can be a handheld moduleconnected to the adjusting device of the trolley by a cabled connectionor a wireless connection. Such a control module can also be realised toissue control signals to the driving device of the trolley, so that itcan be used, for example, to control the motion of the trolley over afactory floor.

The ring segment trolley comprises a supporting device or carrying bed,realised to bear the armature ring segment in an horizontal orientationunderneath the armature assembly. To ensure that the ring segment istransported in a safe and secure manner, such a supporting device orcarrying bed is shaped in a concave manner in keeping with the curvedform of a stator ring segment. Since the stator ring segment istransported in an horizontal position, i.e. in a “lying” position, theadjusting device is realised to raise or lower the ring segment relativeto the free ring segment portion of the armature assembly. In otherwords, an adjusting device is realised to have an vertical direction oftravel.

The adjusting device can comprise any suitable moving parts that can becontrolled to alter a vertical or horizontal orientation of the ringsegment that is carried by the ring segments trolley. In an embodimentof the application, the adjusting device comprises a plurality ofindividually moveable adjusting points. The adjusting device comprisesthree individually moveable adjusting points, since three suchindividually movable adjusting points are sufficient to obtain anydesired orientation of the ring segment relative to the stator bedframe.An adjusting point comprises a linear actuator such as a hydrauliccylinder and piston arrangement that can be actuated to extend orcontract along its direction of travel. In one realisation, theadjusting points can be controlled simultaneously, so that the ringsegment is raised or lowered evenly without altering its orientation.However, sometimes a slight adjustment may need to be made to one sideor corner of the ring segment. In addition to or as an alternative tothe preceding embodiment, each adjusting point can be controlled oractuated independently of the others. With such an arrangement ofindividually controllable adjusting points, the adjusting device can berealised to raise the armature ring segment in an upward verticaldirection towards the free ring segment portion of the partiallyassembled armature, and can “fine tune” the position of the ring segmentrelative to the free ring segment portion of the stator bedframe.

The step of bringing the ring segment into position relative to thestator bedframe, so that these can be connected, can be assisted by oneor more sensors. For example, a laser or sonic measurement device can beused to determine a distance between a point on the ring segment and acorresponding “target” point on the stator bedframe. Such a signal canbe used by the control module or control interface and can be used asthe basis for control signals sent to the adjusting points of thetrolley.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features of the present application will becomeapparent from the following detailed descriptions considered inconjunction with the accompanying drawings. It is to be understood,however, that the drawings are designed solely for the purposes ofillustration and not as a definition of the limits of the application.

FIG. 1 shows a perspective view of an armature assembly apparatusaccording to an embodiment of the application;

FIG. 2 shows a side view of the armature assembly apparatus of FIG. 1with a partially assembled armature;

FIG. 3 shows a frontal view of the armature assembly apparatus of FIG. 1with the partially assembled armature in a first stage of assembly;

FIG. 4 shows a frontal view of the armature assembly apparatus of FIG. 1with the partially assembled armature in a second stage of assembly;

FIG. 5 shows a frontal view of the armature assembly apparatus of FIG. 1with the partially assembled armature in a third stage of assembly.

DETAILED DESCRIPTION OF INVENTION

In the diagrams, like numbers refer to like objects throughout. Objectsin the diagrams are not necessarily drawn to scale.

FIG. 1 shows a perspective view of an armature assembly apparatus 1according to an embodiment of the application. The armature assemblyapparatus 1 comprises a large robust stator transport frame 2, and inthis example also comprises four rollers 23 or wheels 23, one at eachcorner, so that the transport frame 2 can be moved from one location toanother, for example in an assembly line. The transport frame 2 alsocomprises a turning device 20, 21, 22, in this case a set of meshedgears, wherein a large gear 20 can be moved by driving a smaller gear21. To this end, a motor 22 or other driving device 22, indicatedschematically here, can be connected to the smaller driving gear 21. Themotor 22 can be mounted to the stator frame, or can be arrangedelsewhere, as appropriate. Such a motor can comprise a shaft or othertransmission for connecting to the driving gear 21. The large gear 20 isarranged around a hollow shaft 25 which is realised or shaped toaccommodate a shaft of an armature or stator. The diagram also shows aring segment conveyance 3 or trolley 3, which is freely movable relativeto the stator transport frame 2. The ring segment trolley 3 comprises aflatbed body 30 connected to four rollers 32 or wheels 32, and asupporting device 31 shaped to accommodate a curved ring segment. Thissupporting device 31 is arranged on a number of linear actuators 33,which, as will be shown later, can be controlled to adjust to theposition of the supporting device 31 in a vertical direction. To ensurethat the trolley is correctly aligned underneath the stator assembly, itcan be guided using, for example, markings on the floor.

FIG. 2 shows a side view of the armature assembly apparatus 1 of FIG. 1with a partially assembled armature 4, referred to as the stator 4 inthe following, for a generator of a direct-drive wind turbine. Abedframe of the stator 4 comprises a hollow shaft 40, a backplate 42 anda frontplate 41. The annular backplate 42 is mounted to the shaft 40 ona tower interface side, i.e. the side of the shaft that will face intothe nacelle of the wind turbine. The frontplate 41 will face into thehub of the wind turbine. A cooling system 43 with components such asencasement, fan, heat exchanger, tubing etc. are arranged as indicatedhere in the space between the backplate 42 and the frontplate 41. In agenerator for a direct-drive wind turbine, the stator bedframe cancomprise 5 m or more in diameter, and the distance between thefrontplate and backplate can comprise about 1.5 m to 2 m.

The diagram also shows the ring segment trolley 3 with a stator ringsegment 5 lying in the supporting device 31 ready for mounting to thestator bedframe 4. A stator ring segment 5 comprises copper windings 50arranged on a bedframe interface 51. The bedframe interface 51 isrealised to be mounted to an outer rim of the frontplate 41 andbackplate 42, as will be explained in the following. In the diagram, nostator ring segments have yet been mounted to the stator bedframe 4.

FIG. 3 shows a frontal view of the armature assembly apparatus of FIG. 1with the partially assembled stator 4 in a first stage of assembly.Here, one ring segment 5 has already been mounted. A second ring segment5 is in place on the supporting device 31 of the ring segment trolley 3.A controller 6, here indicated schematically, is used to drive the ringsegment trolley 3, for example by sending control signals 62 to a motoror other driving device (not shown here) of the ring segment trolley 3.One or more sensors 60, positioned at some suitable position on the ringsegment trolley 3, can send measurement signals 61 to the controller 6,so that this can react accordingly. The sensor 60 can detect therelative position of the ring segment 5 relative to the statorfrontplate 41 and backplate 42, for example by using guiding device 420of the stator frontplate 41 and backplate 42 as reference points. Thecontroller 6 can send appropriate adjustment signals 62 to the trolley 3to adjust the position of the ring segment 5 relative to the statorfrontplate 41 and backplate 42 until the position of the stator ringsegment 5 is considered satisfactory. Since the ring segment 5 is onlyelevated while it rests on the cradle of the trolley 3, an elasticdeformation of the ring segment 5 is avoided. Furthermore, thishorizontal position is the same position that will be taken by the ringsegment 5 during operation of the wind turbine. Since the stator plates41, 42 are primarily designed to bear the weight of the ring segments 5in a horizontal position, these are also effectively protected from anydistortion.

FIG. 4 shows a frontal view of the armature assembly apparatus of FIG. 1with the partially assembled stator 4 in a second stage of assembly.This diagram shows a next stage in the mounting process. The controller6 can send adjustment signals 63 to the linear actuators 33 of the ringsegment trolley 3 so that the supporting device 31 can be raised to therequired height in a vertical direction D as indicated in the diagram.Again, a sensor 60 can deliver measurement signals 61 to the controller6 so that this can respond by issuing appropriate control signals 63. Abedframe interface 51 of the stator ring segment 5 is designed so that,once it has been brought into a mounting position relative to thefrontplate 41 and backplate 42, it can be slotted into place. This canbe achieved by appropriate control signals 62, 63 issued by thecontroller 6.

FIG. 5 shows a frontal view of the armature assembly apparatus of FIG. 1with the partially assembled armature in a third stage of assembly. Inthis diagram, almost all of the ring segments 5 have mounted onto thestator bedframe 4, 41, 42. The diagram clearly shows another stator ringsegment 5 with its windings wrapped, for example, in a fibreglass bandto protect the windings, arranged on the trolley 3 ready for mounting.The stator bedframe 4 has been rotated in the direction indicated sothat the second-last free ring segment portion 420 is brought into asuitable position for mounting of the next stator ring segment 5.

Once the stator bedframe 4, 41, 42 has been filled with ring segments 5,the stator transport frame 2 can be moved to a next assembly position bythe rollers 24 mounted on the four corners of the transport frame 2.

Although the present application has been disclosed in the form ofembodiments and variations thereon, it will be understood that numerousadditional modifications and variations could be made thereto withoutdeparting from the scope of the application.

For the sake of clarity, it is to be understood that the use of “a” or“an” throughout this application does not exclude a plurality, and“comprising” does not exclude other steps or elements. The mention of a“unit” or a “module” does not preclude the use of more than one unit ormodule.

1. An armature assembly apparatus for assembling an armature of anelectrical machine, comprising: an armature holding apparatus forholding a partially assembled armature so that a rotation axis of thearmature is horizontal; a rotating device for rotating the partiallyassembled armature about the rotation axis; an armature ring segment;and a ring segment conveyance for conveying the armature ring segment toa mounting position relative to a free ring segment portion of thepartially assembled armature.
 2. The armature assembly apparatusaccording to claim 1, wherein the rotating device is realised to rotatethe partially assembled armature about its rotation axis.
 3. Thearmature assembly apparatus according to claim 1, wherein the armatureholding apparatus comprises a connecting device for detachablyconnecting the partially assembled armature to the rotating device. 4.The armature assembly apparatus according to claim 1, wherein therotating device comprises a meshed gear arrangement.
 5. The armatureassembly apparatus according to claim 1, wherein the rotating device isrealised to rotate the partially assembled armature by a radial amountcorresponding to a radial width of a free ring segment portion.
 6. Thearmature assembly apparatus according to claim 1, further comprising anadjusting device for bringing the armature ring segment into themounting position on the free ring segment portion of the partiallyassembled armature.
 7. The armature assembly apparatus according toclaim 6, further comprising a control interface for controlling theadjusting device.
 8. The armature assembly apparatus according to claim1, wherein the armature holding apparatus comprises an actuating devicefor actuating the rotating device to rotate the partially assembledarmature about the rotation axis.
 9. A ring segment conveyance forassembling an armature of an electrical machine, comprising: a supportfor supporting an armature ring segment; and a positioning device forbringing the armature ring segment into a mounting position relative toa free ring segment portion of a partially assembled armature.
 10. Thering segment conveyance according to claim 9, further comprising anadjusting device for adjusting the mounting position of the armaturering segment relative to the free ring segment portion of the partiallyassembled armature.
 11. The ring segment conveyance according to claim9, wherein the adjusting device comprises a plurality of individuallycontrollable adjusting points.
 12. The ring segment conveyance accordingto claim 11, wherein one of the adjusting points comprises a linearactuator.
 13. The ring segment conveyance according to claim 9, whereinthe adjusting device is realised to raise the armature ring segment inan upward vertical direction towards the free ring segment portion ofthe partially assembled armature.
 14. A method for assembling anarmature of an electrical machine, comprising: connecting a partiallyassembled armature to an armature holding apparatus so that a rotationaxis of the armature is horizontal; actuating a rotating device torotate the partially assembled armature about the rotation axis to bringa free ring segment portion into a position; conveying an armature ringsegment to the armature holding apparatus for mounting onto the freering segment portion of the partially assembled armature; controlling apositioning device of the armature assembly apparatus to bring thearmature ring segment into a mounting position on the free ring segmentportion of the partially assembled armature; and fastening the armaturering segment to the free ring segment portion of the partially assembledarmature at the mounting position.
 15. The method according to claim 14,further comprising repeating the steps until a desired number ofarmature ring segments have been mounted onto the armature.